We study the magnetotransport properties of dual-gated graphene bilayers, in which the total density and layer density imbalance are independently controlled. As the bilayer is imbalanced we observe the emergence of a quantum Hall state (QHS) at filling factor ν=0 evinced by a plateau in the Hall conductivity, consistent with the opening of a gap between the electron and hole bands. By varying the layer density imbalance at fixed total density, we observe a suppression of the QHS at filling factors ν=8 and ν=12 when the layer densities are balanced, an observation at variance with theoretical expectations in the absence of electron-electron interaction and disorder.
@article{arxiv.0909.2288,
title = {Quantum Hall effect in dual-gated graphene bilayers with tunable layer density imbalance},
author = {Seyoung Kim and E. Tutuc},
journal= {arXiv preprint arXiv:0909.2288},
year = {2009}
}